Seniority number in spin-adapted spaces and compactness of configuration interaction wave functions

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This work extends the concept of seniority number, which has been widely used for classifying N-electron Slater determinants, to wave functions of N electrons and spin S, as well as to N-electron spin-adapted Hilbert spaces. We propose a spin-free formulation of the seniority number operator and per...

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Autores principales: Massaccesi, Gustavo Ernesto, Oña, Ofelia Beatriz
Publicado: 2013
Materias:
Change of basis
Configuration interactions
Expectation values
Natural orbitals
Quantitative evaluation
Rapid convergence
Slater determinants
Unitary transformations
Electrospinning
Magnetic moments
Molecular orbitals
Wave functions
Acceso en línea:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00219606_v139_n8_p_Alcoba
http://hdl.handle.net/20.500.12110/paper_00219606_v139_n8_p_Alcoba
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Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id paper:paper_00219606_v139_n8_p_Alcoba
record_format dspace
spelling paper:paper_00219606_v139_n8_p_Alcoba2023-06-08T14:44:24Z Seniority number in spin-adapted spaces and compactness of configuration interaction wave functions Massaccesi, Gustavo Ernesto Oña, Ofelia Beatriz Change of basis Configuration interactions Expectation values Natural orbitals Quantitative evaluation Rapid convergence Slater determinants Unitary transformations Electrospinning Magnetic moments Molecular orbitals Wave functions This work extends the concept of seniority number, which has been widely used for classifying N-electron Slater determinants, to wave functions of N electrons and spin S, as well as to N-electron spin-adapted Hilbert spaces. We propose a spin-free formulation of the seniority number operator and perform a study on the behavior of the expectation values of this operator under transformations of the molecular basis sets. This study leads to propose a quantitative evaluation for the convergence of the expansions of the wave functions in terms of Slater determinants. The non-invariant character of the seniority number operator expectation value of a wave function with respect to a unitary transformation of the molecular orbital basis set, allows us to search for a change of basis which minimizes that expectation value. The results found in the description of wave functions of selected atoms and molecules show that the expansions expressed in these bases exhibit a more rapid convergence than those formulated in the canonical molecular orbital bases and even in the natural orbital ones. © 2013 AIP Publishing LLC. Fil:Massaccesi, G.E. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Oña, O.B. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. 2013 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00219606_v139_n8_p_Alcoba http://hdl.handle.net/20.500.12110/paper_00219606_v139_n8_p_Alcoba
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Change of basis
Configuration interactions
Expectation values
Natural orbitals
Quantitative evaluation
Rapid convergence
Slater determinants
Unitary transformations
Electrospinning
Magnetic moments
Molecular orbitals
Wave functions
spellingShingle Change of basis
Configuration interactions
Expectation values
Natural orbitals
Quantitative evaluation
Rapid convergence
Slater determinants
Unitary transformations
Electrospinning
Magnetic moments
Molecular orbitals
Wave functions
Massaccesi, Gustavo Ernesto
Oña, Ofelia Beatriz
Seniority number in spin-adapted spaces and compactness of configuration interaction wave functions
topic_facet Change of basis
Configuration interactions
Expectation values
Natural orbitals
Quantitative evaluation
Rapid convergence
Slater determinants
Unitary transformations
Electrospinning
Magnetic moments
Molecular orbitals
Wave functions
description This work extends the concept of seniority number, which has been widely used for classifying N-electron Slater determinants, to wave functions of N electrons and spin S, as well as to N-electron spin-adapted Hilbert spaces. We propose a spin-free formulation of the seniority number operator and perform a study on the behavior of the expectation values of this operator under transformations of the molecular basis sets. This study leads to propose a quantitative evaluation for the convergence of the expansions of the wave functions in terms of Slater determinants. The non-invariant character of the seniority number operator expectation value of a wave function with respect to a unitary transformation of the molecular orbital basis set, allows us to search for a change of basis which minimizes that expectation value. The results found in the description of wave functions of selected atoms and molecules show that the expansions expressed in these bases exhibit a more rapid convergence than those formulated in the canonical molecular orbital bases and even in the natural orbital ones. © 2013 AIP Publishing LLC.
author Massaccesi, Gustavo Ernesto
Oña, Ofelia Beatriz
author_facet Massaccesi, Gustavo Ernesto
Oña, Ofelia Beatriz
author_sort Massaccesi, Gustavo Ernesto
title Seniority number in spin-adapted spaces and compactness of configuration interaction wave functions
title_short Seniority number in spin-adapted spaces and compactness of configuration interaction wave functions
title_full Seniority number in spin-adapted spaces and compactness of configuration interaction wave functions
title_fullStr Seniority number in spin-adapted spaces and compactness of configuration interaction wave functions
title_full_unstemmed Seniority number in spin-adapted spaces and compactness of configuration interaction wave functions
title_sort seniority number in spin-adapted spaces and compactness of configuration interaction wave functions
publishDate 2013
url https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00219606_v139_n8_p_Alcoba
http://hdl.handle.net/20.500.12110/paper_00219606_v139_n8_p_Alcoba
work_keys_str_mv AT massaccesigustavoernesto senioritynumberinspinadaptedspacesandcompactnessofconfigurationinteractionwavefunctions
AT onaofeliabeatriz senioritynumberinspinadaptedspacesandcompactnessofconfigurationinteractionwavefunctions
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